RE: [PipingDesign] Re: Piping problem

From: <Ed>
Date: Thu Oct 31 2002 - 08:35:00 EST

Dear Patrick,

Does BOS Fluid software address fluid water hammer and also siphoning effect?

How much does the software run?


ed engalan

-----Original Message-----
From: patburgh2001 [] Sent: Wednesday, October 30, 2002 11:53 AM To:
Subject: [PipingDesign] Re: Piping problem

Dear David,

There are several software programs available today for the type of analysis you want to do. They will shut the pump off, follow an unloading curve,compute vapor sizes, and help you size vacuum breakers. Several of the more common ones are Pipenet, LIQT, and our BOS Fluids.

We also help customers setup and use the software, and provide engineering assistance. All of the suggestions I've read that have come from other members of the group are certainly true. The software just helps you quantify the effects and predict things like cavity size, maximum pressure surges, minimum suction heads, etc.

Patrick Vaughan LaLonde Paulin Research Group


Piping engineers for years have labored with simplifying hand methods, or overly sophisticated software products when needing basic steady state and transient fluid analysis capability. BOS Fluids was written specifically to address the need of the piping engineer for fluid analysis information,and to provide a system whereby the fluid simulation results can be easily integrated back into the piping system design and analysis.
BOS Fluids is an interactive computer simulation package that models steady state and transient flow in liquid or gas carrying piping systems. The procedure is easy to use and is interactive with pipe stress programs. The package contains the elements required to model almost any unsteady flow condition. The elements included in the simulation package are pipes, valves, pumps, equipment, surge vessels, inlets, outlets, and orifices.
BOS Fluids makes fluid simulation simple and easily accessible and gives the analyst conservative pressure transients and dynamic force results.
Based on a number of realistic assumptions a simplified form of the unsteady conservation (Navier-Stokes) equations are solved. The assumptions made are:
1. Fluid behavior in pipes is one dimensional i.e. similarity of cross sectional distribution of properties does exist.

2. Fluid transport velocity is small compared to wave speed.
3. Wave fronts remain plane while propagating.
4. Gas simulations assume that flow velocities are below sonic, and
that pressure drops through the system are less than 30%. Based on these approximations friction effects are lumped. The present friction model used is Colebrook-White. The Darcy-Weisbach flow model is used for steady state pressure drop calculations and the basic theory applied in BOS Fluids can be found in Wylie & Streeter's "Fluid Transients" published by FEB Press. BOS Fluids is capable of simulating both the steady and transient behavior of liquid carrying closed conduit systems of pipes,valves, pumps and surge relief devices. The following special features are available: 1. Pipe stress models from either CAESAR or PipePak can be downloaded for fluid analysis.
2. The analyst can pick different fluids from a database or add their own fluids to the database
3. Two different models are available to simulate column separation: Concentrated Air Pocket (CAP) model and the Vapor Cavity Model (VCM). 4. Various pipe materials can be applied-both isotropic (Metals) and Orthotropic (FRP) materials are included. 5. Based on geometry typical pump properties are generated automatically.
6. Buried and above ground systems can be simulated. 7. Simultaneously the transient response of multiple sources: Pump starts, Pump Failures, Valve Operations can be simulated. 8. Harmonic option allows an analysis of the occurrence of standing waves.
9. Maximum and minimum pressures and velocities occurring during transient and/or harmonics are traced.
10. The force processor allows an analyst to survey the time history of the unbalanced forces on pipe sections and preprocesses the force time histories to be used in the dynamical module of the pipe stress program.
11. A spectrum breakdown of force time histories is available. The analyst can see the natural frequencies of the fluid response that tend to excite the piping system.
12. Both Metric (SI) and English Units can be selected. Typical analyses using BOS Fluids include: water transmission and distribution systems, main cooling water systems for chemical plants, sewage water systems, combined power and drinking water cycle power stations, oil product transport lines, tanker loading and unloading systems and dynamical behavior of chemical liquid transport lines.

> Hi Everyone,
> I've recently started my first main job as a trainee mechanical
> engineer. One of the first problems ive came across is to modify a

Texas Flange - a good source for information on industrial flanges, all they ask is for referrals for designs they help with. 877-610-8924.


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